International application No. WO 92/11931 (NAPHTACHIMIE et al.), discloses a method of producing chemical substances in which one or more reagents are caused to flow inside a tube disposed in a radiation zone of a furnace, and in which a portion of the tube is subjected to vibration so as to limit deposition of reaction by-products on the inside wall of the tube. That document proposes imparting transverse vibration to the tube at a frequency lying in the range 50 Hz to 2000 Hz by means of a mechanical vibration source which is disposed inside or outside the radiation zone of the furnace, and which is connected to the tube by means of a mechanical link.
That document also describes a furnace, such as a steam cracking furnace, including a radiation thermal enclosure fitted with burners and within which there is disposed a cracking tube that is sinuous in shape, being constituted by a succession of straight sections interconnected by bends. The furnace is provided with excitation means suitable for generating vibration in at least a portion of the tube, which means may be constituted by a mechanical vibration generator connected to the tube by a mechanical link.